Facile LaOF: Sm3+ based labeling agent and their applications in residue chemistry of latent fingerprint and cheiloscopy under UV–visible light

Luminescent lanthanum oxyfluoride nano inorganic materials were considered to be prospective building blocks for multifunctional applications. This offers new potentials in surface-based science comprising of visualization of latent fingerprint (LFPs) and lips print on non-porous surfaces. Traditional visualization techniques possess high backward hindrance, low sensitivity, complicated setup and poor visibility. To overcome with these problems, LaOF:Sm3+ (5 mol%) nanopowder (NPs) prepared via sonochemical route were explored. Photoluminescence (PL) emission spectra exhibit strong emission peaks at ∼566 nm, 607 nm, 653 nm and 708 nm attributed to 4G5/2 → 6H5/2, 4G5/2 → 4H7/2, 4G5/2 → 6H9/2 and 4G5/2 → 6H11/2 intra-4f orbital transitions of Sm3+ ions respectively. Estimated photometric properties confirm that the material emits warm orange red color. Therefore, the synthesized phosphor materials may quite be useful for LFPs recovery, cheiloscopy and optoelectronics applications. Keywords: Ultrasonication, Photoluminescence, Forensic, Cheiloscopy, Solid state lighting